Methods and apparatus to load a valve packing

ABSTRACT

Methods and apparatus to load a valve packing are described. An example apparatus to load a valve packing includes a load assembly having a biasing element disposed between a valve packing flange and a stop flange to provide a load to a seal assembly. The packing flange is adjustable relative to the stop flange to adjust the load to be applied to the seal. A first guide member coupled to the packing flange or the stop flange provides a first predetermined distance between the packing flange and the stop flange. The first guide member provides an indication of a first predetermined load to be provided by the load assembly when the packing flange and the stop flange are spaced at the first predetermined distance provided by the first guide member.

CROSS-REFERENCE TO RELATED APPLICATION

This patent claims the benefit of U.S. Provisional Application Ser. No.61/225,155, filed on Jul. 13, 2009, which is hereby incorporated byreference in its entirety.

FIELD OF THE DISCLOSURE

This disclosure relates generally to fluid valves and, moreparticularly, to methods and apparatus to load a valve packing.

BACKGROUND

Process control plants or systems often employ fluid valves, such asrotary valves, linear valves, etc., to control the flow of processfluids. In general, fluid valves typically include a fluid flow controlmember that is disposed in the fluid path and which is operativelycoupled to an actuator such as, for example, a pneumatic actuator, amanual actuator, etc. A valve stem or shaft operatively couples the flowcontrol member to the actuator, which moves the flow control memberbetween an open position and a closed position to allow or restrictfluid flow between an inlet and an outlet of the valve. Typically, thevalve stem or shaft extends between the flow control member and theactuator through a bonnet coupled to the valve body.

A valve packing or packing assembly is often employed to preventundesired leakage of process fluid to the environment through the valvebody along the valve stem or shaft. The valve packing may include aplurality of springs and/or packing seals disposed along a portion ofthe valve stem or shaft to provide a seal. Some known valve packingsemploy a high-spring rate loading device or spring assembly (e.g.,Belleville springs) to provide a relatively high load over a relativelysmall range of deflection or compression. However, such known loadingdevices typically require very precise deflections and/or tightly heldmanufacturing tolerances to enable a desired packing stress to beapplied to the packing seals.

Failure to provide a desired packing stress to the packing seals maycause an improper seal. For example, a packing stress that is too lowmay cause the process fluid to leak to the environment through thepacking seals. A packing stress that is too large (e.g., greater than amaximum recommended packing stress) may cause some types of packingseals (e.g., graphite seals) to transfer material to a valve stem,thereby causing build-up of material on the valve stem and damaging thepacking seal. Additionally or alternatively, packing stresses that aretoo high may increase packing friction between the packing seals and thevalve stem or shaft, which may reduce valve performance and/or theoperational life of the valve packing and/or the valve stem or shaft.

SUMMARY

In one example, an apparatus to load a valve packing includes a loadassembly having a biasing element disposed between a valve packingflange and a stop flange to provide a load to a seal assembly. Thepacking flange is adjustable relative to the stop flange to adjust theload to be applied to the seal. A first guide member is coupled to thepacking flange or the stop flange to provide a first predetermineddistance between the packing flange and the stop flange. The first guidemember provides an indication of a first predetermined load to beprovided by the load assembly when the packing flange and the stopflange are spaced at the first predetermined distance provided by thefirst guide member.

In another example, a packing assembly for use with a valve includes aseat assembly disposed within a bore of a valve bonnet to provide afluid seal around a valve stem or shaft. A first flange is operativelycoupled to the seal assembly via a packing retainer and the first flangehas a first opening. A second flange is disposed between the valvebonnet and the first flange and the second flange has a second opening.A biasing element is disposed between the first flange and the secondflange and provides a packing stress to the seal assembly. A first guidemember is disposed within the first opening of the first flange or thesecond opening of the second flange to provide a first predetermineddistance between the first flange and the second flange that correspondsto a first predetermined packing stress to be provided to the sealassembly.

In yet another example a method to load a valve packing includesadjusting a packing flange nut to a position corresponding at leastapproximately to a free condition of a biasing assembly and coupling afirst gauge member to a first flange. The method further includesadjusting a gap between a first surface of the first gauge member and areference surface opposite the first flange to a first predetermineddistance. The method further includes tightening the packing flange nutso that the first surface of the first gauge member substantially alignswith the reference surface and causes a load assembly to provide a firstpredetermined packing stress to the valve packing when the first gaugemember substantially aligns with the reference surface.

In yet another example, a valve packing assembly includes means forproviding a load to a seal assembly and means for providing anindication of a first predetermined load to be provided by the means forproviding a load. The valve packing also includes means for coupling themeans for providing an indication to the means for providing a load suchthat the means for providing an indication provides a predetermineddistance between a first reference flange of the means for providing aload and a second reference flange of the means for providing load wherethe predetermined distance corresponds to the first predetermined load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a known fluid control valve.

FIG. 1B is an enlarged view of a known valve packing of the fluid valveshown in FIG. 1A.

FIGS. 2A and 2B illustrate another known valve packing that may be usedto implement the fluid valve of FIG. 1A.

FIGS. 3A-3C illustrate an example valve packing assembly describedherein.

FIGS. 4A-4C illustrate another example load assembly described hereinthat may be used to implement the valve packing assembly of FIGS. 3A-3C.

FIGS. 5A and 5B illustrate another example load assembly describedherein that may be used to implement the valve packing assembly of FIGS.3A-3C.

FIG. 6 illustrates yet another example load assembly described hereinthat may be used to implement the valve packing assembly of FIGS. 3A-3C.

FIGS. 7A-7D illustrate yet another example load assembly describedherein that may be used to implement the valve packing assembly of FIGS.3A-3C.

FIGS. 8 and 9 illustrate positive stop apparatus that may be used withthe example valve packing assembly of FIGS. 7A-7D.

FIGS. 10A and 10B illustrate yet another example load assembly describedherein that may be used to implement the valve packing assembly of FIGS.3A-3C.

DETAILED DESCRIPTION

In general, the example methods and apparatus described herein provideprecise control of packing stresses for live-load valve packings. Morespecifically, the example valve packing apparatus described hereininclude a load assembly that provides a desired or predetermined packingstress to a packing seal assembly based on a predetermined distance ordeflection of a biasing element (e.g., a Belleville spring). The exampleload assemblies described herein enable precise control of an amount ofdeflection of a biasing element. In particular, controlling thedeflection of the biasing element to a predetermined position, the loadassemblies may be adjusted to provide a substantially constant desiredpacking stress to a packing seal assembly.

Additionally, the example methods and apparatus described herein enablea packing stress to be set or adjusted without causing a biasing element(e.g., a Belleville spring) to be fully compressed. Also, in someexamples, precisely controlling packing stress may prevent packingmaterial transfer to a valve stem and/or reduce friction between thepacking seal and a valve stem or shaft. The example methods andapparatus described herein may also compensate for variations in stackheight of multiple biasing elements as a result of material thicknessvariations of the elements (e.g., stack-up tolerances).

In particular, a valve packing apparatus described herein may include afirst guide member that provides an indication of a packing stressapplied to a packing seal assembly. The first guide member may preventor restrict a load assembly from applying a packing stress to thepacking seal assembly that is greater than a first predetermined packingstress (e.g., a nominal desired packing stress). In some examples, thevalve packing apparatus may also include a second guide member toprovide an indication of a second packing stress provided to the packingseal assembly. The second guide member may prevent or restrict the loadassembly from applying a packing stress to the packing seal assemblythat is greater than a second predetermined packing stress (e.g., amaximum desired packing stress).

In some examples, the load assembly of the valve packing assembly orapparatus includes a plurality of biasing elements (e.g., Bellevillesprings) disposed or stacked (e.g., in series) between a packing flangeand a stop flange. A first guide member may be coupled to the packingflange or the stop flange to provide a first predetermined distancebetween the packing flange and the stop flange. The first guide membermay provide an indication of the packing stress provided by the loadassembly when the packing flange and the stop flange are spaced thefirst predetermined distance provided by the first guide member.

Before describing the example valve packing apparatus, a briefdiscussion of a known pneumatically actuated fluid control valve 100 isprovided in connection with FIG. 1A. The known fluid control valve 100shown in FIG. 1A includes an actuator 102 operatively coupled to a valvebody 104 via a bonnet 106. The valve body 104 defines a fluid flowpassageway 108 between an inlet 110 and an outlet 112. A valve plug 114is disposed within the fluid flow passageway 108 and includes a seatingsurface 116 that cooperates with a valve seat 118 to control a port area120 through which fluid may flow between the inlet 110 and the outlet112. A valve stem 122 couples the valve plug 114 to an actuator stem124. The actuator stem 124 couples the valve stem 122 and the valve plug114 to the actuator 102. The bonnet 106 includes a bore 126 to slidablyreceive the valve stem 122 and houses a valve packing assembly 128.

The valve packing assembly 128 provides a seal to prevent leakage ofprocess fluid past the valve stem 122 and/or protects the environmentagainst the emission of hazardous or polluting fluids. In other words,the valve packing assembly 128 provides a seal that opposes the pressureof the process fluid flowing through the valve 100. Thus, the valvepacking assembly 128 must be properly or sufficiently loaded to providea packing seal that can oppose the pressure of the process fluid flowingthrough the valve 100.

FIG. 1B depicts an enlarged split, partial cross-sectional view of thefluid control valve 100 of FIG. 1A. The left side of FIG. 1B shows thevalve packing assembly 128 in a compressed or stressed condition and theright side of FIG. 1B shows the valve packing assembly 128 in anuncompressed or unstressed condition. As shown in FIG. 1B, the valvepacking assembly 128 includes a packing flange 130 coupled to the bonnet104 via packing studs 132 and packing nuts 134. A packing material orseal assembly 136 surrounds the valve stem 122 and is disposed withinthe packing bore 126 of the bonnet 104. The packing material 136 istypically compressed axially to ensure that an inner bore or surface 138of the packing material 136 is sealed against the valve stem 122 andthat an outer surface 140 of the packing material 136 is sealed againstthe bore 126 of the bonnet 104. Axially loading the packing material 136about an axis 142 causes the packing material 136 to expand radially toeffect a dynamic seal on the moving valve stem 122 and a static seal inthe packing bore 126 where the packing material 136 is in contact withthe packing bore 126. As shown in FIG. 11I, the packing material or sealassembly 36 includes packing seals 144, packing rings 146, and a packingbox ring 148.

In the illustrated example, a plurality of biasing elements or springs150 (e.g., Belleville springs) may be positioned or stacked in seriesbetween the packing flange 130 and a flange or shoulder 152 of a packingfollower 154. The packing nuts 134 may be used to adjustably drive orurge the springs 150 against the packing follower 154 which, in turn,axially compresses the packing material 136 to provide a seal andprevent leakage of process fluid past the valve stem 122. As the packingnuts 134 are tightened on the packing studs 132, the packing flange 130transmits a load to the springs 150. The springs 150 deflect or compressas the packing nuts 134 are tightened to provide a packing stress (e.g.,an axial load) to the packing material 136 via the packing follower 154.

In this example, the springs 150 provide a live-load valve packing byproviding a uniform load to the packing material 136 and maintainingsuch a uniform packing load during valve operation (e.g., valvestroking). In other words, the springs 150 provide a substantiallyconstant load to the packing follower 154 to exert a substantiallyconstant compressive force on the packing material 136. Thus, if thepacking material 136 consolidates (e.g., due to wear), the springs 150decompress to move the packing follower 154 toward the bonnet 104 tomaintain a compressive force the packing material 136 and therebymaintain the seal integrity of the packing material 136.

Operating conditions (e.g., a temperature and/or a pressure of a processfluid) often determine the type of packing material to be used toprovide an adequate seal for the particular process fluid orapplication. Some known packing materials such as, for example, graphitepacking materials may be used in severe service conditions (e.g.,process fluid temperatures greater than 450 F, pressures greater than4,500 psig). However, such graphite packing materials may need to beprecisely loaded with a proper packing stress or load to optimallyfunction and/or provide a proper seal.

In the example of FIG. 1B, the springs 150 are Belleville springs.Typically, Belleville springs may be used to provide a relatively largeloading force or packing stress to compress packing materials that areused in severe service conditions (e.g., high pressure applications). Ingeneral, a Belleville spring provides a relatively high packing stressrelative to the travel or deflection imparted on the Belleville spring.In other words, a Beluville spring has a relatively high spring constantand, thus, a small or relatively low deflection or compression of aBelleville spring provides a relatively high packing stress or force.For example, Belleville springs that are stacked in series provide aload based on a proportion or the amount of deflection of the stack ofBelleville springs (e.g., a percent of deflection relative to the stackheight), regardless of the number Belleville springs stacked in series.

Additionally, live-load valve packings generally have tolerance stack-updue to material thickness variations between different springs. Becausethe Belleville springs generally provide a relatively highforce-to-compression ratio (i.e., a high spring rate), such tolerancestack-up is an important consideration to precisely control the load orpacking stress. Ignoring such a tolerance stack-up may cause the springsto provide a load that is greater than a maximum desired load, which maycause a packing material to fracture, transfer to a valve stem orotherwise become compromised.

Thus, Belleville springs typically need to be precisely compressed ordeflected to provide a desired packing stress. Otherwise, if the packingstress provided is too high, high packing friction may result, which canreduce valve performance and/or reduce packing material operating life.Additionally, a packing stress that is relatively high or greater than amaximum desired packing stress may cause some packing materials such asgraphite packing materials to transfer material to a valve stem, whichmay cause an improper seal or premature failure.

Referring to FIG. 1B, one method to adjust or control the deflection ofthe springs 150 is to measure a torque applied to the packing nuts 134by using, for example, a torque wrench. However, a torque wrench may beunreliable due to, for example, variability of lubrication on thepacking stud 132 and/or the packing nuts 134, different manufacturingprocesses used to form threads of the packing studs 132, the number oftimes the packing studs 132 and the packing nuts 134 have been used,etc. Such inaccurate loading from torque measurements may causeinaccurate packing stresses or loads to be applied to the packingmaterial 136. As a result premature failure of the packing material 134may occur even if the torque reading on the torque wrench indicates anacceptable torque measurement. Thus, measuring the packing nut torque todetermine a proper packing stress may not be adequate to preventpremature failure of some packing materials such as a graphite packingmaterials.

Another method to control packing stress is to position the springs 150to a maximum compression, flat or solid condition as shown in the leftside of FIG. 1B by tightening the packing nuts 134. In this manner,compressing or deflecting tile springs 150 to the fully flat or solidcondition provides an indication of the maximum possible load that canbe provided by the springs 150. The packing nuts 134 are then loosenedor backed off a certain amount (e.g., one-quarter of a turn or rotation)to decompress the springs 150 to a desired position that provides anominal or desired packing stress to the packing material 136. Forexample, an operator or maintenance person subsequently loosens thepacking nuts 134 a precise number of rotations or portion of a rotation(e.g., one-quarter of a rotation) to set the packing stress to a desiredstress level. However, in some instances, compressing or deflecting thesprings 150 to the fully flat or solid condition may cause the springs150 to set or deform in the fully compressed or flat condition, therebypermanently damaging the springs 150.

In another example, a method to control packing stress is to initiallyhand tighten the packing nuts 134 such that the springs 150 arepositioned to the uncompressed or free stack height of the springs 150as shown in the right side of FIG. 1B. An operator or maintenance personthen measures the uncompressed free height of the springs 150 or thedistance between the shoulder 152 of the retainer 154 and a surface 156of the packing flange 130. The packing nuts 134 are then tightened untilthe springs 150 are filly (e.g., 100%) compressed or substantially flator solid as shown in the left side of FIG. 1B. The operator ormaintenance person then measures the height of the flat or compressedcondition of the springs 150. The packing nuts 134 are then loosened todecompress the springs 150 to a desired predetermined measured heightbetween the uncompressed and the fully compressed heights. Again, thismethod requires the springs 150 to be fully compressed, which may damagethe springs 150 or may cause the springs 150 to provide a different loadwhen the springs 150 are decompressed to the desired height compared toa load provided by the springs 150 at the predetermined desired heightprior to being fully compressed.

FIGS. 2A and 2B illustrate another known valve packing assembly 200 thatmay be used to implement the fluid control valve 100 of FIG. 1A. Thevalve packing assembly 200 includes biasing elements or springs 202(e.g., Belleville springs) stacked or disposed between a packing flange204 and a packing retainer or follower 206. One or more gauges or loadscales 208 may be coupled to the packing flange 204 to provide anindication of an amount of compression or deflection of the springs 202and, thus, an indication of the packing stress imparted to a packingseal 210 (e.g., a graphite seal). To adjust the load scale 208, thesprings 202 are compressed slightly and the packing flange 204 is movedto the free stack height position of the springs 202. The load scale 208is coupled to the packing flange 204 via fasteners 212 such that abottom edge 214 of tile load scale 208 aligns with an indicator disk 216when the springs 202 are in the free stack height position (as shown inFIG. 2A). Once the load scale 208 is coupled to the packing flange 204,packing nuts 218 may be tightened to align the indicator disk 216 with aminimum compression line or marking 220 or a maximum compression line ormarking 222 on the load scale 208.

Although the load scale 208 provides a visual indication of the packingstress, the load scale 208 does not provide a positive stop to preventdeflection or compression of the springs 202 beyond a deflectionindicated by the maximum compression line 222. Thus, the packingmaterial 210 may be subjected to a packing stress that is greater than amaximum desired packing stress if the springs 202 are deflected to aposition beyond the position indicated by the maximum compression line222.

Furthermore, the load scale 208 is sized for a particular valve stemsize (e.g., a diameter of a valve stem). For maximum operating life andto operate the valve packing assembly 200 within a desired range ofpacking friction between a valve stem 224 and the packing material 210,a load scale must be used with a corresponding valve stem size. However,this configuration may be prone to human error. Additionally, the valvepacking assembly 200 uses larger sized (e.g., larger diameter) springs202 to provide a deflection that can be visually measured via the gaugescale 208. However, such a configuration enlarges the overall envelopeof the valve packing assembly 200 and may not be suitable forapplications in which an overall smaller footprint is required.

FIGS. 3A and 3B illustrate different views of an example live-load valvepacking assembly 300 described herein. Referring to FIGS. 3A-3C, theexample valve packing assembly 300 includes a load assembly 302 toprovide a load or packing stress to a packing material or seal assembly304. The seal assembly 304 (e.g., a graphite packing seal assembly) isdisposed within a packing bore 306 of a bonnet 308 to provide a fluidseal around a valve stem 310 slidably received by the packing bore 306.Axially loading the seal assembly 304 about an axis 312 causes the sealassembly 304 to expand radially to effect a dynamic seal on the movingvalve stern 310 and a static seal in the packing bore 306 where an outersurface 314 of the seal assembly 304 is in contact with the packing bore306. The bonnet 308 couples a valve (e.g., the valve 104 of FIG. 1A) toan actuator (e.g., the actuator 102 of FIG. 1A). The packing bore 306slidably receives the valve stem 310 as the actuator moves the valvestem 310 between a first position (e.g., an open position) and a secondposition (e.g., a closed position).

The load assembly 302 is removably coupled to the bonnet 308 via packingstuds 316 a and 316 b and packing nuts 318 a and 318 b. The packing nuts318 a-b are threadably coupled to the respective packing studs 316 a-band are turned (e.g., tightened or loosened) to adjust the loading orpacking stress on the seal assembly 304 within the bonnet 308 and aroundthe valve stem 310. The bonnet 308 also includes threaded bores 320 tothreadably receive the packing studs 316 a-b.

In this example, the load assembly 302 includes a first flange orpacking flange 322 and a second flange or stop flange 324. The packingflange 322 and the stop flange 324 include respective central openings326 and 328 (FIG. 3C) to slidably receive the valve stem 310. Thepacking flange 322 includes an aperture 330 that coaxially aligns withan aperture 332 of the stop flange 324 to slidably receive the packingstud 316 a. As most clearly shown in FIG. 3B, the aperture 330 of thepacking flange 322 and the corresponding aperture 332 of the stop flange324 are sized slightly larger than the diameter of the packing stud 316a so that the packing flange 322 and the stop flange 324 can move in arectilinear direction along the valve stem 310 (i.e., the axis 312).

In this example, the load assembly 302 includes biasing elements orsprings 334 that are disposed or stacked between the packing flange 322and the stop flange 324. In this example, the biasing elements 334include a plurality of Belleville springs stacked in series between thepacking flange 322 and the stop flange 324 to provide a load or packingstress to the seal assembly 304.

As shown in FIGS. 3A-3C, the packing flange 322 includes an aperture 336a having an axis 338 that is substantially parallel to, but spaced adistance from, an axis 340 of an aperture 342 a of the stop flange 324.A first guide member or stop screw 344 a is coupled to the packingflange 322 via the aperture 336 a and a second guide member or stopscrew 346 a is coupled to the stop flange 324 via the second aperture342 a. However, in other examples, the packing flange 322; may onlyinclude the aperture 336 a to receive the first guide member 344 a orthe stop flange 324 may only include the aperture 342 a to receive thesecond guide member 346 a.

In illustrated example, the first guide member 344 a is positionedrelative to the stop flange 324 to provide a first predetermineddistance between the packing flange 322 and the stop flange 324. Forexample, the first guide member 344 a is positioned such that thepacking flange 322 deflects the biasing elements 334 an amountcorresponding to a predetermined packing stress. Thus, the firstpredetermined distance provides an indication of a first predeterminedload to be provided to the seal assembly 304 when the packing flange 322and the stop flange 324 are spaced at the first predetermined distanceprovided by the first guide member 344 a. The first guide member 344 aalso provide a mechanical stop to prevent the load assembly 302 fromapplying a load to the seal assembly 304 that is greater than the firstpredetermined load. For example, the first predetermined distance maycorrespond to a nominal packing stress to be provided to the sealassembly 304.

The second guide member 346 a is coupled to the stop flange 324 andpositioned relative to the packing flange 322 to provide a secondpredetermined distance between the packing flange 322 and the stopflange 324. For example, the second guide member 346 a is positionedsuch that the packing flange 322 deflects the biasing elements 334 anamount corresponding to a second predetermined packing stress when thepacking flange 322 and the stop flange 324 are spaced a distanceprovided by the second guide member 346 a. Thus, the second guide member346 a provides an indication of a second predetermined load to beprovided to the seal assembly 304 when the packing flange 322 and thestop flange 324 are spaced at the second predetermined distance. Thesecond guide member 346 a also provides a mechanical stop to prevent theload assembly 302 from applying a load to the seal assembly 304 that isgreater than a second predetermined load that corresponds to the secondpredetermined distance between the packing flange 322 and the stopflange 324 provided by the second guide member 346 a. For example, thesecond predetermined load may correspond to a maximum desired packingstress to be provided to the seal assembly 304.

The valve packing assembly 300 also includes a packing retainer orpacking follower 348 to operatively couple the load assembly 302 to theseal assembly 304. In this example, the stop flange 324 is positionedbetween the packing retainer 348 and the packing flange 322. Thus, theload assembly 302 provides a load to the seal assembly 304 via thepacking retainer 348. As shown, the packing retainer 348 includes afollower flange 350 disposed between a base portion 352 and a sleeveportion 354. The packing retainer 348 is disposed between the stopflange 324 and the seal assembly 304 such that an edge 356 of the baseportion 352 engages the seal assembly 304 and the follower flange 350engages a surface 358 of the stop flange 324. The sleeve portion 354 issized to slidably fit within the central openings 326 and 328 of thepacking flange 322 and the stop flange 324. The packing retainer 348includes an opening 360 to slidably receive the valve stem 310 and maybe lined with carbon filled Polytetrafluoroethylene (PTFE) or othersuitable material. In this example, the load assembly 302 is operativelycoupled to the seal assembly 304 via the packing retainer 348. The loadassembly 302 applies a load to the packing retainer 348 to move thepacking retainer 348 in a rectilinear direction along the axis 312toward the seal assembly 304.

The example load assembly 302 enables precise control over a desiredpacking stress imparted to the seal assembly 304 by enabling precisecontrol of the amount of deflection of the biasing elements 334. Suchaccurate control of the packing stress significantly improves theperformance of the valve packing assembly 300 and significantly reducespacking stress variability compared to known live-load valve packingssuch as those described in connection with FIGS. 1B, 2A, and 2B.

To precisely control the packing stress, the valve packing assembly 300is assembled as shown in FIGS. 3A-3C. The packing nuts 318 a-b areadjusted to a position corresponding to at least approximately a freecondition or free stack height of the biasing elements 334. For example,the packing nuts 318 a-b may be hand tightened to a free stack heightposition of the biasing elements 334 such that the packing flange 322provides a relatively light load on the biasing elements 334. In thismanner, the biasing elements 334 and/or the packing flange 322 may beaccurately or approximately positioned to the free stack height of thebiasing elements 334.

When the valve packing assembly 300 is in the free stack heightcondition, the first guide member 344 a is adjusted (e.g., via a tool)such that a first gap G₁ (e.g., a gap of 0.122 inches) is formed betweena reference surface 362 of the first guide member 344 a and a referencesurface 364 of the stop flange 324. Although not shown, a gauge tool maybe used to measure the gap G₁. Additionally or alternatively, the secondguide member 346 a is adjusted (e.g., via a tool) such that a second gapG₂ (e.g., a gap of 0.164 inches) is formed between a reference surface366 of the second guide member 346 a and a reference surface 368 of thepacking flange 322. Fasteners 370 (e.g., a lock nut) lock or secure theposition of the first and second guide members 344 a and 346 a to therespective packing flange 322 and the stop flange 324 after thepredetermined gaps G₁ and G₂ are adjusted.

The packing nuts 318 a-b are turned or tightened until the referencesurface 362 of the first guide member 344 a engages the referencesurface 364 of the stop flange 324. The packing nuts 318 a-b may bealternately turned or tighten to maintain the packing flange 322substantially parallel with the stop flange 324. As shown in thisexample, the packing flange 322 includes an aperture (not shown) toreceive a third guide member 344 b and the stop flange 324 includes anaperture (not shown) to receive a fourth guide member 346 b to helpmaintain the packing flange 322 substantially parallel to the stopflange 324 and/or a surface 372 of the bonnet 308 when loading the sealassembly 304. In other examples, a plurality of apertures may be spacedabout a periphery of the packing flange 322 to receive a plurality ofguide members spaced at the first gap G₁ relative to the stop flange 324and/or a plurality of apertures may be spaced about the periphery of thestop flange 324 to receive a plurality of guide members spaced at thesecond gap G₂ relative to the packing flange 322.

In this example, the first guide member 344 a provides a mechanical stopto prevent further movement of the packing flange 322 toward the stopflange 324 when the reference surface 362 of the first guide member 344a engages the reference surface 364 of the stop flange 324. Ifadditional torque is applied to the packing nuts 318 a-b (i.e., thepacking nuts are tightened) when the first guide member 344 a engagesthe stop flange 324, the first guide member 344 a will not allowadditional loading to be imparted to the seal assembly 304. Instead, thefirst guide member 344 a will absorb or take the additional loading.

As noted above, biasing elements such as Belleville springs that arestacked in series provide a load based on the amount of deflectionexerted on the stack of biasing elements regardless of the overallheight of the stack of biasing elements. In other words, the first gapG₁ between the first guide member 344 a and the stop flange 324 providesa predetermined distance to control the deflection of the biasingelements 334 between the position of the packing flange 322corresponding to a free stack height position of the biasing elements334 and the position of the packing flange 322 relative to the stopflange 324 when the first guide member 344 a engages the stop flange324.

Thus, a first set of biasing elements (e.g., a stack of three Bellevillesprings) having a first stack height will provide a load to the sealassembly 304 when deflected an amount corresponding to the first gap G₁that is substantially equal to a load provided by a second different setof biasing elements (e.g., a stack of three Belleville springs) having asecond stack height different from the first stack height (e.g., due tostack-up tolerance) where the second set of biasing elements isdeflected to a position corresponding to the first gap G₁. Thus, thevalve packing assembly 300 limits the packing stress applied to the sealassembly 304 to a load that corresponds to the amount of deflectionprovided by the first predetermined distance or the first gap G₁.Additionally or alternatively, by adjusting the first guide member 344 ato the first gap G₁ after the packing flange 322 is positioned to thefree stack height of the biasing elements 334, tolerance stack-up of thebiasing elements 334 is controlled and does not affect the amount ofload imparted on the seal assembly 304. Additionally or alternatively,in other examples, the gaps G₁ and G₂ may be adjusted (e.g., increased)proportionately as a function of the stack height of the biasingelements (e.g., a stack of five Belleville springs). In other words, thegaps G₁ and G₂ may be adjusted to provide a predetermined amount orpercentage of deflection relative to the stack height of the biasingelements stacked in series to provide a load that corresponds to theamount of deflection imparted on the biasing elements.

To provide a maximum packing stress, the first guide member 344 a ispositioned or moved (e.g., removed) such that at least a gap between thefirst guide member 344 a and the stop flange 324 is greater than thesecond gap G₂. The packing nuts 318 a-b are then tightened until thereference surface 368 of the packing flange 322 engages the referencesurface 366 of the second guide member 346 a. In this example, thesecond guide member 346 a provides a mechanical stop to prevent furthermovement of the packing flange 322 toward the stop flange 324 when thereference surface 366 of the second guide member 346 a engages thereference surface 368 of the packing flange 322.

The first and second gaps G₁ and G₂ of the respective first and secondguide members 344 a and 346 a may be set at the factory and/or adjustedin the field. Additionally, the loading may be adjusted (e.g., increasedor decreased) by adjusting the first and/or second gaps G₁ and G₂ of therespective first guide member 344 a or the second guide member 346 a.For example, the first guide member 344 a and/or the second guide member346 a may be repositioned a predetermined distance by, for example,turning the first guide member 344 a or the second guide member 346 a apredetermined number of turns or a partial turn.

During operation, wear of the seal assembly 304 may cause the stopflange 324 and the packing retainer 348 to move toward the seal assembly304, thereby causing the reference surface 362 of the first guide member344 a to move away from the reference surface 364 of the stop flange324. The biasing elements 334 may decompress but continue provide asubstantially constant load to the seal assembly 304. Duringmaintenance, the packing nuts 31Ba-b can be tightened so that the firstguide member 344 a engages the stop flange 324. In other examples, thefirst gap G₁ can be readjusted and the packing nuts 318 a-b can betightened so that the first guide member 344 a engages the stop flange324.

The example valve packing assembly 300 may be used with stroke valves(e.g., the fluid control valve 100), rotary valves, or any other type offluid control device that requires a live-loaded valve packing.

FIGS. 4A-4C illustrate different views of another example load assembly400 that may be used to implement the example valve packing assembly 300to provide a predetermined load or packing stress. Although the exampleload assembly 400 is described in connection with the valve packingassembly 300, the load assembly 400 may be used or associated with anyother suitable valve packing assembly.

Those components of the example load assembly 400 of FIGS. 4A-4C thatare substantially similar or identical to those components of theexample load assembly 302 described above and that have functionssubstantially similar or identical to the functions of those componentswill not be described in detail again below. Instead, the interestedreader is referred to the above corresponding descriptions in connectionwith FIGS. 3A-3C. Those components that are substantially similar oridentical will be referenced with the same reference numbers as thosecomponents described in connection with FIGS. 3A-3C.

Referring to FIGS. 4A-4C, the load assembly 400 includes biasingelements 402 disposed between a packing flange 404 and a stop flange406. In this example, in contrast to the load assembly 300 of FIGS.3A-3C, an aperture 408 of the packing flange 404 is coaxially alignedwith an aperture 410 of the stop flange 406. A first guide member 412 isdisposed in the aperture 408 of the packing flange 404 and a secondguide member 414 is disposed in the aperture 410 of the stop flange 406.In this example, packing flange 404 includes a third guide member 416coaxially aligned with a fourth guide member (not shown) of the stopflange 406 to help maintain the packing flange 404 substantiallyparallel to the stop flange 406 and/or the surface 372 of the bonnet 308when the load assembly 400 is being adjusted to provide a load to theseal assembly 304.

During assembly, the packing nuts 318 a-b are tightened so that thebiasing elements 402 deflect slightly to provide a relatively light loadto position the packing flange 404 to approximately the free stackheight position of the biasing elements 402. As most clearly shown inFIG. 4C, a first predetermined gap 418 is provided between a referencesurface 420 of the first guide member 412 and a reference surface 422 ofthe second guide member 414. Additionally, a second predetermined gap424 is provided between the reference surface 422 of the second guidemember 414 and a reference surface 426 of the packing flange 404. In theillustrated example, the second guide member 414 is positioned to thesecond predetermined gap 424 and then the first guide member 412 ispositioned to the first predetermined gap 418. Fasteners 428 (e.g., locknuts) lock or secure the positions of the first and second guide members412 and 414 to the packing flange 404 and the stop flange 406,respectively, after the predetermined gaps 418 and 424 are set oradjusted. The predetermined gaps 418 and 424 may be factory set or maybe field adjusted.

To load the seal assembly 304 to a predetermined packing stressassociated with the first predetermined gap 418, the packing nuts 318a-b are tightened (e.g., hand tightened) until the reference surface 420of the first guide member 412 engages the reference surface 422 of thesecond guide member 414. To load the seal assembly 304 to apredetermined packing stress associated with the second predeterminedgap 424, the first guide member 412 is removed or positioned such that agap between the reference surface 420 of the first guide member 412 andthe reference surface 422 of the second guide member 414 is greater thanthe second predetermined gap 424. The packing nuts 318 a-b are thentightened until the reference surface 426 of the packing flange 404engages the reference surface 422 of the second guide member 414.

In this example, the first guide member 412 provides a mechanical stopto prevent or restrict the load assembly 400 from applying a packingstress to the seal assembly 304 that is greater than the packing stressassociated with the first predetermined distance 418. In other words,the first guide member 412 prevents the load assembly 400 fromdeflecting the biasing elements 402 an amount greater than the firstpredetermined distance 418. Likewise, the second guide member 414provides a mechanical stop to prevent or restrict the load assembly 402from applying a packing stress to the seal assembly 304 that is greaterthan the packing stress provided when the biasing elements 402 aredeflected an amount corresponding to the second predetermined distance424.

FIGS. 5A and 5B illustrate different views of yet another example loadassembly 500 described herein that may be used with the example valvepacking assembly 300 of FIGS. 3A-3C.

The example load assembly 500 includes biasing elements or springs 502(e.g., Belleville springs stacked in series) disposed between a packingflange 504 and a stop flange 506. The stop flange 506 includes anaperture 508 to receive a guide member 510 and the packing flange 504includes an aperture 512 coaxially aligned with the aperture 508 of thestop flange 506 to receive a tool 514.

The guide member 510 may be, for example, a socket-head stop screw 516.The tool 514 (e.g., an Allen wrench) may be used to adjust the positionof the guide member 510 via the aperture 512 of the packing flange 504.As shown in this example, a second guide member 518 may be provided tomaintain the packing flange 504 substantially parallel to the stopflange 506 and/or the surface 372 of the bonnet 308 when loading theseal assembly 304. Additionally, the use of the tool 514 may facilitateadjustment of the guide member 510 by counting the number of turns orrotations of the tool 514 during adjustment of the guide member 510.

During assembly, the packing nuts 318 a-b are tightened so that thebiasing elements 502 deflect slightly to provide a relatively light loadto position the packing flange 504 to approximately the free stackheight position of the biasing elements 502. A predetermined gap 520 isprovided between a reference surface 522 of the guide member 510 and areference surface 524 of the packing flange 504. A fastener 526 (e.g., alock nut) may be used to lock or secure the position of the guide member510 after the predetermined gap 520 is adjusted. The predetermined gap520 may be factory set and/or may be adjusted in the field.

To load the seal assembly 304 to a predetermined packing stressassociated with the predetermined gap 520, the packing nuts 318 a-b aretightened until the reference surface 522 of the guide member 510engages the reference surface 524 of the packing flange 504. The packingnuts 318 a-b cause the packing flange 504 to move toward the stop flange506 until the packing flange 504 engages the guide member 510, therebycausing the biasing elements 502 to deflect a predetermined distancecorresponding to the predetermined gap 520.

The predetermined gap 520 may correspond to a maximum desired packingstress, a nominal packing stress, or any desired packing stress to beimparted to the seal assembly 304. For example, the predetermined gap520 may be adjusted to provide a predetermined distance between thepacking flange 504 and the stop flange 506 that deflects the biasingelements 502 to provide a maximum desired packing stress to the sealassembly 304. Thus, if the predetermined gap 520 is associated with amaximum packing stress, the packing nuts 318 a-b may then be loosened tocause the reference surface 524 of the packing flange 504 to move awayfrom the reference surface 522 of the guide member 510 to provide apacking stress that is less than tile packing stress provided when thepacking flange 504 engages the guide member 510. The packing nuts 318a-b may be loosened a predetermined number of turns (e.g., 1 turn) fromthe position in which the packing flange 504 engages guide member 510 todecompress or reduce the deflection of the biasing elements 502 to acontrolled desired packing stress that is less than the maximum packingstress.

The example guide member 510 is not limited to a socket-head stop screwas shown in FIGS. 5A and 51B. For example, as shown in FIG. 6, anexample load assembly 600 includes a guide member 602 having hex-shapedhead or portion 604. Additionally or alternatively, in this example, apacking flange 606 may be provided without having to manufacture (e.g.,machine) apertures (e.g., the aperture 512 of FIGS. 5A and 5B) toreceive a tool (e.g., the tool 514). Instead, a tool may access theguide member 602 between the packing flange 606 and a stop flange 608.

FIGS. 7A-7D illustrate different views of yet another example loadassembly 700 that may be used to implement the example valve packingassembly 300 of FIGS. 3A-3B. The example load assembly 700 includesbiasing elements 702 disposed between a packing flange 704 and a gaugeflange 706. In this example, a first guide member 708 a is coupled tothe gauge flange 706 and is at least partially received by a firstaperture 710 a of the packing flange 704. A second guide member 712 adifferent from the first guide member 708 a is coupled to the gaugeflange 706 and is at least partially received by a second aperture 710 bof the packing flange 704. In this example, a third guide member 708 bsubstantially similar to the first guide member 708 a is coupled to thegauge flange 706 and received by an aperture 710 c of the packing flange704. A fourth guide member 712 b substantially similar to the secondguide member 712 a is coupled to the gauge flange 706 and received by anaperture 710 d of the packing flange 704. The apertures 710 a-d and theguide members 708 a-b and 712 a-b are spaced about a periphery of therespective packing flange 704 and the gauge flange 706 to facilitatemaintaining the packing flange 704 substantially parallel to the gaugeflange 706 when loading the seal assembly 304.

Referring the FIG. 7C, the first guide member 708 a includes a steppedsurface to provide a first predetermined distance 714 between a first orend surface 716 and a second or reference surface 718. This distancecorresponds to a predetermined gap at which the packing flange 704 maybe set to provide a deflection to the biasing elements 702 that providesa predetermined packing stress to the seal assembly 304. For example,such a gap may be set to provide a nominal packing stress to the packingseals.

Referring the FIG. 7D, the second guide member 712 a is a guide pin thatincludes a stepped surface to provide a second predetermined distance720 between a first surface 722 and a second surface 724. The distance720 corresponds to a predetermined gap at which the packing flange 704is positioned to provide a deflection to the biasing elements 702 thatprovides a second predetermined packing stress to the seal assembly 304that is different (e.g., greater than) the first predetermined packingstress. For example, such a gap may be set to provide a maximum desiredpacking stress to the seal assembly 304.

Thus, the example load assembly 700 includes a first set of first guidemembers 708 a-b to indicate, for example, a nominal packing stress to beapplied to the packing seals and a second set of guide members 712 a-bto indicate, for example, a maximum desired packing stress to be appliedto the packing seals.

During assembly, the packing stress may be set at the factory and/or thein the field. The packing nuts 318 a-b are tightened to an initialposition corresponding at least approximately to a free stack heightcondition of the biasing elements 702 (e.g., a hand-tight position). Thefirst guide members 708 a-b and the second guide members 712 a-b arecoupled to the gauge flange 706. When the packing flange 704 is at thefree stack height position, the first and the second guide members 708a-b and 712 a-b are adjusted such that the respective end surfaces 716and 722 substantially align with (e.g., are flush with) a referencesurface 726 (e.g., a top surface) of the packing flange 704. Althoughnot shown, a tool (e.g., a plate, a ruler, etc.) may be used todetermine if the end surfaces 716 and 722 are substantially aligned withthe reference surface 726 of the packing flange 704. For example, a flatruler may be held against the reference surface 726 over the aperture710 a of the packing flange 704 and the first guide members 708 a-b andthe second guide members 712 a-b may be adjusted until the end surface716 engages the ruler.

To set the packing stress to the packing stress provided when thebiasing elements 702 are deflected to the first predetermined distance714 (e.g., the nominal packing stress), the packing nuts 318 a-b aretightened until the reference surface 718 of the first guide members 708a-b substantially aligns with the reference surface 726 of the packingflange 704. Again, a tool may be used to determine that the referencesurface 718 of the first guide members 708 a-b is substantially alignedwith the reference surface 726 of the packing flange 704. Similarly, toadjust the packing stress to the packing stress provided when thebiasing elements 702 are deflected to the second predetermined distance720 (e.g., the maximum desired packing stress), the packing nuts 318 a-bare further tightened until the reference surface 724 of the secondguide members 712 a-b substantially align with the reference surface 726of the packing flange 704.

FIG. 8 illustrates an example positive stop 800 that may be used withthe example load assembly 700 of FIGS. 7A-7D. The positive stop 800includes a cylindrical body 802 having a threaded portion 804 tothreadably couple to the aperture 710 a of the packing flange 704. Thepositive stop 800 includes a first aperture 806 and a counterbore 808.The first aperture 806 is sized to receive a portion 8 10 of a guidemember 812 between an end surface 814 and a reference surface 816 of theguide member 812. In this example, the guide member 812 has a diameterthat is smaller than the diameter of the guide member 708 a of FIGS.7A-7C. Alternatively, the aperture 710 a of the packing flange 704 maybe sized larger (e.g., have a larger diameter) to receive a largerpositive stop member having a counterbore to receive, for example, theguide member 708 a.

In this example, the counterbore 808 is sized to slidably receive theguide member 812. The reference surface 816 of the guide member 812engages a shoulder 818 formed between the counterbore 808 and theaperture 806 to prevent the packing flange 704 from moving toward thegauge flange 706 (see FIG. 7B). Thus, the positive stop 800 preventsdeflection of the biasing elements 702 beyond the deflection providedwhen the reference surface 816 engages the shoulder 818. In this manner,the positive stop 800 prevents the load assembly (e.g., the loadassembly 702 of FIG. 7B) from applying a load to the seal assembly 304that exceeds the packing stress associated with the predetermineddistance provided by the guide member 812. In some examples, a thicknessof the gauge flange 706 may be increased.

FIG. 9 illustrates another example positive stop 900 that may be usedwith the example load assembly 700 of FIGS. 7A-7D. In this example, thepositive stop 900 is formed (e.g., integrally formed) in the packingflange 704. In this example, a counterbore 902 is formed within theaperture 710 a of the packing flange 704. The counterbore 902 may besized to form a shoulder 904 that engages a reference surface 906 of aguide member 908. The shoulder 904 is spaced a distance from thereference surface 726 of the packing flange 704 so that when an endsurface 910 of the guide member 908 is flush with the reference surface726 of the packing flange 704, the guide member 908 can only travel inrectilinear motion toward the reference surface 726 a predetermineddistance 912. Alternatively, a portion of the guide member 908 may besized (e.g., may be increased in length) to provide a predetermineddistance (e.g., a predetermined distance greater than the predetermineddistance 912) between the reference surface 726 and the referencesurface 906.

Thus, the positive stop 900 prevents the deflection of the biasingelements 702 beyond the deflection provided by the predetermineddistance 912 to prevent the load assembly 700 from applying a packingstress to the seal assembly 304 that exceeds a packing stress thatcorrelates to the predetermined distance 912 provided by the guidemember 908. In other examples, the aperture 710 b may be formed with thepositive stop 900 to prevent the load assembly 700 from applying apacking stress that is greater than the packing stress associated with asecond predetermined distance.

FIGS. 10A and 10B illustrate different views of yet another example loadassembly 1000 that may be used with the example valve packing assembly300. In this example, the load assembly 1000 includes biasing elements1002 disposed between a packing flange 1004 and a gauge flange 1006. Aguide member 1008 is coupled to the gauge flange 1006 and is at leastpartially received by an aperture 1010 of the packing flange 1004. Incontrast to the guide members 708 a-b and 708 c-d of FIGS. 7A-7D, theguide member 1008 includes multiple stepped surfaces spaced apart atdifferent predetermined distances or gap measurements that correspond torespective predetermined packing stresses to be applied by the biasingelements 1002.

In this example, as shown in FIG. 10B, the guide member 1008 includes afirst stepped surface to provide a first predetermined distance or gap1012 between an end surface 1014 and a first reference surface 1016. Theguide member 1008 also includes a second stepped surface to provide asecond predetermined distance or gap 1018 between the end surface 1014and a second reference surface 1020. The example guide member 1008reduces the number of apertures (e.g., the apertures 710 b-d) requiredin the packing flange 1004 and the gauge flange 1006, thereby reducingmanufacturing costs. The method to adjust the load assembly 1000 issubstantially similar to the method of adjusting the load assembly 700described above in connection with FIGS. 7A-7D and, thus, will not berepeated. Instead, the interested reader is directed to the descriptionof the load assembly 700 described above in connection with FIGS. 7A-7D.

Although certain methods and apparatus have been described herein, thescope of coverage of this patent is not limited thereto. To thecontrary, this patent covers all methods and apparatus fairly fallingwithin the scope of the appended claims either literally or under thedoctrine of equivalents.

1. An apparatus to load a valve packing, comprising: a load assemblyhaving a biasing element disposed between a valve packing flange and astop flange to provide a load to a seal assembly, wherein the packingflange is adjustable relative to the stop flange to adjust the load tobe applied to the seal; and a first guide member coupled to a firstaperture of the packing flange or a second aperture of the stop flangeto provide a first predetermined distance between the packing flange andthe stop flange, wherein the first guide member provides an indicationof a first predetermined load to be provided by the load assembly whenthe packing flange and the stop flange are spaced at the firstpredetermined distance provided by the first guide member.
 2. Anapparatus as defined in claim 1, wherein the first guide member is tomechanically stop the load assembly from applying a load to the sealthat is greater than the first predetermined load.
 3. An apparatus asdefined in claim 1, wherein the first guide member is disposed withinthe first aperture of the packing flange or the second aperture of thestop flange.
 4. An apparatus as defined in claim 1, further comprising asecond guide member coupled to the other of the first aperture of thepacking flange or the second aperture of the stop flange to provide asecond predetermined distance between the packing flange and the stopflange, wherein the second guide member provides an indication of asecond predetermined load to be provided by the load assembly when thepacking flange and the stop flange are spaced at the secondpredetermined distance provided by the second guide member.
 5. Anapparatus as defined in claim 4, wherein the second guide member is tomechanically stop the load assembly from applying a load to the sealassembly that is greater than the second predetermined load.
 6. Anapparatus as defined in claim 4, wherein the second guide member isdisposed within the first aperture of the packing flange or the secondaperture of the stop flange.
 7. An apparatus as defined in claim 4,wherein the first guide member is coaxially aligned with the secondguide member.
 8. An apparatus as defined in claim 4, wherein the firstpredetermined load comprises a nominal packing stress to be provided tothe seal assembly and the second predetermined load comprises a maximumpacking stress to be provided to the seal assembly.
 9. An apparatus asdefined in claim 1, wherein the guide member comprises a fastener or apin.
 10. An apparatus as defined in claim 9, wherein the pin includes afirst stepped surface to provide an indication of the firstpredetermined load.
 11. An apparatus as defined in claim 10, wherein thepin includes a second stepped surface to provide an indication of thesecond predetermined load.
 12. An apparatus as defined in claim 11,further comprising a stop removably coupled to the packing flange andcoaxially aligned with the pin to mechanically stop the load assemblyfrom applying a load to the seal assembly that is greater than a maximumpredetermined load.
 13. A packing assembly for use with a valve,comprising: a seal assembly to be disposed within a bore of a valvebonnet to provide a fluid seal around a valve stem or shaft; a firstflange to be operatively coupled to the seal assembly via a packingretainer, the first flange having a first opening; a second flange to bedisposed between the valve bonnet and the first flange, the secondflange having a second opening; a biasing element to be disposed betweenthe first flange and the second flange, wherein the biasing element isto provide a packing stress to the seal assembly; and a first guidemember to be disposed within the first opening of the first flange orthe second opening of the second flange to provide a first predetermineddistance between the first flange and the second flange that correspondsto a first predetermined packing stress to be provided to the sealassembly.
 14. The packing assembly of claim 13, further comprising asecond guide member to be disposed within the first opening of the firstflange or the second opening of the second flange to provide a secondpredetermined distance different than the first predetermined distancebetween the first flange and the second flange that corresponds to asecond predetermined packing stress to be provided to the seal assembly.15. A method to load a valve packing, comprising: adjusting a packingflange nut to a position corresponding at least approximately to a freecondition of a biasing assembly; coupling a first gauge member to afirst flange; adjusting a gap between a first surface of the first gaugemember and a reference surface opposite the first flange to a firstpredetermined distance; and tightening the packing flange nut so thatthe first surface of the first gauge member substantially aligns withthe reference surface and causes a load assembly to provide a firstpredetermined packing stress to the valve packing when the first gaugemember substantially aligns with the reference surface.
 16. A method ofclaim 15, further comprising removing the first gauge member from thefirst flange.
 17. A method of claim 16, further comprising adjusting agap between a second surface of a second gauge member and the referencesurface, wherein the second gauge member provides an indication of asecond predetermined packing stress provided to the valve packing whenthe second gauge member substantially aligns with the reference surface.18. A method of claim 15, wherein the first gauge member engages asecond flange opposite the first flange when the load assembly providesthe first predetermined packing stress to the valve packing.
 19. Amethod of claim 15, wherein the reference surface is a surface of asecond flange opposite the first flange or a second surface of a secondgauge member.
 20. A method of claim 19, wherein the reference surfacecomprises a second gauge member coupled to the second flange andcoaxially aligned with first gauge.
 21. A valve packing assembly,comprising: means for providing a load to a seal assembly; means forproviding an indication of a first predetermined load to be provided bythe means for providing a load; means for coupling the means forproviding an indication to the means for providing a load such that themeans for providing an indication provides a predetermined distancebetween a first reference flange of the means for providing a load and asecond reference flange of the means for providing a load, wherein thepredetermined distance corresponds to the first predetermined load. 22.A valve packing assembly of claim 21, wherein the means for providing aload comprises a biasing element disposed between the first referenceflange and the second reference flange, wherein the first referenceflange is movable relative to the second reference flange to increase ordecrease the load provided by the biasing element.
 23. A valve packingassembly of claim 21, wherein the means for providing an indicationcomprises a first fastener threadably coupled to the first referenceflange and spaced a first predetermined distance from a first referencesurface, wherein the first fastener engages the first reference surfaceto provide an indication of the first predetermined load.
 24. A valvepacking assembly of claim 23, further comprising means for providing anindication of a second predetermined load to be provided by the meansfor providing a load.
 25. A valve packing assembly of claim 24, whereinthe means for providing an indication of the second predetermined loadcomprises a second fastener threadably coupled to the second referenceflange and spaced a second predetermined distance from a secondreference surface, wherein the second fastener engages the secondreference surface to provide an indication of the second predeterminedload.